Extraction with solvents

The mixture can be separated by distillation. The primary phosphine is recycled for use ia the subsequent autoclave batch, the secondary phosphine is further derivatized to the corresponding phosphinic acid which is widely employed ia the iadustry for the separation of cobalt from nickel by solvent extraction. With even more hindered olefins, such as cyclohexene [110-83-8] the formation of tertiary phosphines is almost nondetectable. 

The mixture is kept for 3 hours at 105°C after the oxide addition is complete. By this time, the pressure should become constant. The mixture is then cooled to 50°C and discharged into a nitrogen-filled botde. The catalyst is removed by absorbent (magnesium siUcate) treatment followed by filtration or solvent extraction with hexane. In the laboratory, solvent extraction is convenient and effective, since polyethers with a molecular weight above about 700 are insoluble in water. Equal volumes of polyether, water, and hexane are combined and shaken in a separatory funnel. The top layer (polyether and hexane) is stripped free of hexane and residual water. The hydroxyl number, water, unsaturation value, and residual catalyst are determined by standard titration methods. 

Soybeans. Vktuady ad soybeans processed in the United States are solvent-extracted with hexane to recover the od. This traditional process is outlined in Figure 4. Beans arriving at the plant are cleaned and dried, if necessary, before storage. When the beans move from storage to processing, they are cleaned further and may be dried and adowed to equdibrate at 10—11% moisture to facditate loosening of the seed coat or hud. They are then cracked. 

In practice, uranium ore concentrates are first purified by solvent extraction with tributyl phosphate in kerosene to give uranyl nitrate hexahydrate. The purified uranyl nitrate is then decomposed thermally to UO (eq. 10), which is reduced with H2 to UO2 (eq. 11), which in turn is converted to UF by high temperature hydrofluorination (eq. 12). The UF is then converted to uranium metal with Mg (eq. 19). 

For vanadium solvent extraction, Hon powder can be added to reduce pentavalent vanadium to quadrivalent and trivalent Hon to divalent at a redox potential of —150 mV. The pH is adjusted to 2 by addition of NH, and an oxyvanadium cation is extracted in four countercurrent stages of mixer—settlers by a diesel oil solution of EHPA. Vanadium is stripped from the organic solvent with a 15 wt % sulfuric acid solution in four countercurrent stages. Addition of NH, steam, and sodium chlorate to the strip Hquor results in the precipitation of vanadium oxides, which are filtered, dried, fused, and flaked (22). Vanadium can also be extracted from oxidized uranium raffinate by solvent extraction with a tertiary amine, and ammonium metavanadate is produced from the soda-ash strip Hquor. Fused and flaked pentoxide is made from the ammonium metavanadate (23). 

Solvent Extraction. With solvent extraction, organics are separated from a waste by mixing the waste with a solvent capable of dissolving or extracting the organics. The extraction process can have multiple stages and be operated where the solvent and waste pass concurrently or countercurrenfly. 

In recent years researchers at West Virginia University have developed coal-derived pitches on a laboratory scale in quantities sufficient to make 1 kg samples of calcined coke for fashioning graphite test specimens. The pitches were derived by uhlizmg solvent extraction with N-methyl pyrrohdone (NMP). This solvent is able to isolate coal-based pitches m high yield and with low mineral matter content [13]. It is this work that will form the basis of the discussion for the later part of this chapter. 

Table 2. Characteristics of bituminous coals subjected to solvent extraction with NMP...

One approach is to uses solvent extraction with dimethyl formamide (DMF) to remove Cj acetylene and a C, acetylene-propadiene mixture from their steam cracked ethylene and propylene streams. The simple acetylene is sold as welding gas, and the C, stream is sold as starting material for chemical synthesis. 

The Robinson annulation of ethyl acetoacetate and trans-chalcone proceeded smoothly to give 6-ethoxycarbonyl-3,5-diphenyl-2-cyclohexenone in 48 % yield. The product was separated from the ionic liquid by solvent extraction with toluene. In both these reactions, the ionic liquid [HMIM][PF6] was recycled and reused with no reduction in the product yield. 

Solvent extraction with sulphonic acids. G. Y. Markovits and G. R. Choppin, Ion Exch. Solvent Extr., 1973, 3, 51-81 (57). 

The data were collected using fluorescence measurements, which allow both identification and quantitation of the fluorophore in solvent extraction. Important experimental considerations such as solvent choice, temperature, and concentrations of the modifier and the analytes are discussed. The utility of this method as a means of simplifying complex PAH mixtures is also evaluated. In addition, the coupling of cyclodextrin-modified solvent extraction with luminescence measurements for qualitative evaluation of components in mixtures will be discussed briefly. 

In the production of alkyl polyglucosides unreacted higher alcohols like C12-C14 are left in the product. It is possible to remove these unreacted alcohols by solvent extraction with SC ethane ( Sridhar and Mullar, 1995). 

In solvent extraction with TBP, the fluoride complexes form solvated complexes with TBP. The stabilities of such complexes depend on the acidity/concentration of hydrofluoric... 

Air (particulates and gas) Sequential collection on Teflon filters and charcoal tubes solvent extraction with hexane (filters) and carbon disulfide (charcoal tubes) GC/MS Not specified Not specified Dannecker et al. 1990... 

GC of aqueous simulant or water extract of olive oil using cold on-column injector. 1,4 butane diol internal standard Solvent extraction with dichloromethane and concurrent derivatisation with 9-(methylaminomethyl)anthracene. Fluorescent derivatives analysed by HPLC with fluorescence detection... 

Solvent extraction with a weakly acidic reagent,... 

Rice, N. M. Gibson, R. W. Solvent extraction with Cyanex 301 and 302 for the upgrading of chloride leach liquors from lateritic nickel ores. Value Adding through Solvent Extraction, [Papers presented at ISEC 96], Melbourne, Mar. 19-23, 1996, 1, 715-720. 

Alguacil, F. J. Cobo, A. Solvent extraction with LIX 973N for the selective separation of copper and nickel. J. Chem. 

Yamamoto et al. [33] have studied the differential determination of heavy metals according to their oxidation states by flameless atomic absorption spectrometry combined with solvent extraction with ammonium pyrrolidinedithio-carbamate or sodium diethyldithio-carbamate. 

DEPA-TOPO [di (2-ethylhexyl) phosphoric acid and trioctylphosphine oxide] A process for recovering uranium from wet-process phosphoric acid, by solvent extraction with a mixture of the two named reagents. Developed at Oak Ridge National Laboratory and first commercialized in 1978 by Freeport Minerals Corporation and Wyoming Mineral Corporation. 

Dualayer Gasoline A process for extracting mercaptans and other organic sulfur compounds from petroleum distillates by solvent extraction with aqueous sodium or potassium hydroxide and a proprietary solubilizer. 

Phenolsolvan A process for extracting phenols from coke-oven liquor and tar acids from tar by selective solvent extraction with di-isopropyl ether (formerly with -butyl acetate). Developed by Luigi in 1937. 

Phorex [Phosphoric acid extraction] A process for purifying phosphoric acid by solvent extraction with -butyl or n-amyl alcohol. Developed by Azote et Produits Chimiques, France. 

Prayon One of the Wet processes for making phosphoric acid by reacting phosphate rock with sulfuric acid. The byproduct is gypsum, calcium sulfate dihydrate. It uses a compartmentalized, multi-section, lined, concrete reactor, with finishing tanks in which the gypsum crystals mature. In 1990 one third of the wet process phosphoric acid made in the Western World was made in this way. The process was developed in 1977 by the Societe de Prayon, Belgium. Variations are known as PH2, PHI 1, and PH12. One variation uses solvent extraction with isopropyl ether and tri-n-butyl phosphate. 

Solutizer Also spelled Solutiser. An early process for removing sulfur compounds from fuel oil by solvent extraction with alkaline sodium isobutyrate. Developed by Shell Development Company. 

Ligocki MP, Pankow JF. 1985. Assessment of adsorption/solvent extraction with polyurethane foam and adsorption/thermal desorption with Tenax-GC for the collection and analysis of ambient organic vapors. Anal Chem 57 1138-1144. 

E2, EE, El Solvent extraction with sonification, HPLC fractioning, derivatization GC-MS/MS 0.4-1 [42]... 

Difrancesco etal. [18] 22 FMs including PCMs and NMs Digested sewage sludge U.S. - Accelerated solvent extraction with dichloromethane - Silica gel chromatography - GC-MS... 

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